In the past there have been a variety of gas purification and gas decontamination systems developed relying on quite widely different physical and chemical properties for their effective operation. One such method relies on the chemical properties either of the contaminants or the main gas stream constituent and operates by passing the gas through a liquid or over a bed of chemical salts where the contaminant to be removed reacts, because of its chemical nature, preferentially with the liquid or the salt and thereby becomes removed from the stream. A second method employs a physical absorber such as an activated charcoal bed which preferentially absorbs the contaminant gases. A third method employs first means to preferentially ionize the contaminant gas and second and separate means to apply a voltage across the gas to concentrate ions of the contaminant gas at an outlet. The gas in the vicinity of the outlet is pumped out and discarded. Still other methods involve the use of diffusion screens with passages preferentially depending on molecular sizes, temperature traps which remove gases having higher boiling points from those having lower boiling points, and electromagnetic separators which operate to segregate the gases on the basis of their molecular mass.
All of the above means have more or less effectiveness in removing contaminants from gases depending upon the particular amount of contaminant and the nature of the contaminant. If the preferred method in any instance is relatively inefficient, then several stages are cascaded until a proper purification level is reached. In this way an effective system may constitute a complex purification train, even though the particular technique, viewed as a one stage operation, is relatively straightforward. Several of the above techniques, notably the chemical absorption, the physical absorption, the diffusion screen and the temperature traps, present a high impedance to the main flow of gas; that is, the presence of the purification system greatly inhibits the flow of gas through the main stream and thereby causes some inefficiency in the overall application. A gas segregation system based upon electromagnetic separation on the basis of molecular mass generally does not present a high impedance to the main gas flow; however, in a rapid flow it calls for a large magnetic field and in the case of many contaminants, the molecular mass of the contaminants may be quite close to the molecular mass of the main gas flow constituents thereby rendering segregation by this method very difficult. Prior art gas segregation systems based on preferential ionization and the use of an electric field to effect separation require ionizing means separate from the provision of the electric field. Further, such prior art systems do not lend themselves to efficient removal of contaminant gases.